Heat reservoir

ABSTRACT

A fluid reservoir includes a housing shell defining a cavity, and a flexible, resilient water impervious bag-shaped liner mounted in the cavity so as to substantially fill the cavity when the liner is filled with fluid. The liner is formed from a flexible water-imperious sheet by forming the sheet into a cylinder, then forming a water-tight first seam along a bottom edge of the cylinder, then folding outer corners of the first seam over, so as to overlap a center portion of the first seam, and so that bottom edges of the outer corners, once so folded over, register substantially co-linearly within a bottom edge of the center portion of the first seam. An upper portion of the liner is thereby urged to bag open. The upper portion thus forms a substantially frustoconical shape. The upper portion is contiguous with a lower portion of the liner. The lower is portion substantially wedge shaped. The bottom corners overlapping the center portion of the first seam are sealed onto the first seam so as to form a second seal.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Patent Application No. 61/004, 695 filed Nov. 30, 2007 entitled Heat Reservoir.

FIELD OF THE INVENTION

This invention relates to heat reservoirs, and in particular heat reservoir construction used in solar collection systems.

BACKGROUND OF THE INVENTION

It is known that when making a heat reservoir primarily for use in solar heating applications that a supporting structure lined with a fluid impermeable material may be a cost effective method of construction. There are many instances of lined pressure vessels, but few instances of lined atmospheric pressure heat reservoirs.

In the prior art to applicant's knowledge applicant is aware of U.S. Pat. No. 4,314,602 entitled “Knock-down Heat Storage Tank” which issued to Frederick, et al. on Feb. 9, 1982, and teaches a knock-down tank for containing a liquid medium, the tank is disassemblable rigid container having a bottom panel, an inner wall, separate upright side-wall panels with inner walls resting on the bottom panel and having abutting side, and having a top panel overlying the side-wall panels thus closing the container. The container is snugly fitted with a liquid-containing flexible liner having side walls fitting snuggly within said side panels and having a bottom wall supported by said bottom panel. The walls of the liner lie against sheets of insulating material. A dip tube extends down into the liner through a hole in the top panel, thereby providing access to the liquid in the container.

SUMMARY OF THE INVENTION

The present invention serves as a heat reservoir for liquids such as water used in heat transfer applications such as solar collection. The reservoir is cost effective to manufacture, consisting in one embodiment of sheet metal wrapped and joined to form an open ended cylinder placed on an insulating base. The cylinder is lined with a fluid tight membrane on the inside such as EPDM roofing rubber sheet (or other flexible mater tight sheet), and insulated on the outside. The lid is similarly constructed with a vapor barrier sheet of fluid tight membrane, a lid made of support material covered with insulation. The egress for the fluid circulation lines and the heat pump transfer lines is through a section of the upper rim of the cylindrical tank and the lid. The fluid tight membrane is a sheet bonded into a cylindrical section formed, prior to lifting with fluid, in the form of a frusto-conical upper portion and a wedge-shape lower portion. The bottom seam is reinforced by a clamp to ensure a water tight seal.

In summary, the non-pressurized fluid reservoir according to one aspect of the present invention includes a housing shell defining a cavity, and a flexible water impervious bag-shaped liner mounted in the cavity so as to substantially fill the cavity when the liner is filled with fluid. The liner is formed from a flexible water-imperious sheet by forming the sheet into a cylinder, then forming a water-tight first seam along a bottom edge of the cylinder, then folding outer corners of the first seam over, so as to overlap a center portion of the first seam, and so that bottom edges of the outer corners, once so folded over, register substantially co-linearly within a bottom edge of the center portion of the first seam. An upper portion of the liner is thereby urged to bag open. The upper portion thus forms a substantially frustoconical shape. The upper portion is contiguous with a lower portion of the liner. The lower is portion substantially wedge shaped. The bottom corners overlapping the center portion of the first seam are sealed onto the first seam so as to form a second seal. The liner may be resilient.

In one embodiment the sheet is formed into the cylinder by sealing opposite ends of the sheet to one another along a third seam once the sheet has been curled into a cylindrical shape. The housing shell may also be substantially cylindrical, and may be sized so that the upper portion of the liner fits snugly inside the cavity of the shell.

In use the lower portion of the liner folds under the upper portion of the liner when the liner is mounted in the cavity. When mounted in the cavity an upper edge of the liner registers with an upper rim of the housing shell. The rim extends around an upper opening into the cavity.

The lower portion of the liner folds under the upper portion to form a floor surface of the liner and to flatten the floor surface of the liner down against a substantially horizontal supporting surface under said housing shell. In one embodiment, the housing shell is open-bottomed, and the supporting surface is a separate insulated platform surface, separate from the shell. When fluid fills the liner in the cavity, the floor surface of the liner spreads out substantially to meet wall or walls of the shell.

In one embodiment, the upper edge of the liner is foldable or folded over to form a lip. The rim of the housing shell may also further include a radially spaced apart array of liner-engaging protrusions to engage and lock to the folded-over lip.

The liner may further include a clamp. The clamp is clamped over said bottom corners and the center portion of the first seam when abutting together of bottom corners over the center portion of the first seam.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying figures wherein similar characters of reference denote corresponding parts in each view:

FIG. 1 is, in front elevation view, the assembled heat reservoir of the present invention.

FIG. 1 a is a side cutaway view along line 1A-1A in FIG. 1.

FIG. 2 is, in front perspective exploded view, the heat reservoir of FIG. 1.

FIG. 3 is, in enlarged front perspective view, the formed sheet metal cylinder of FIG. 2.

FIG. 3 a is, in enlarged partially-cutaway front perspective detail view, a portion of the sheet metal cylinder of FIG. 3.

FIG. 4 is, in front perspective view, the sheet metal cylinder of FIG. 2, reinforced with iron.

FIG. 4 a is, in enlarged partially cutaway front perspective detail view, a portion of the metal cylinder of FIG. 4.

FIG. 5 a is, in perspective view, the fluid tight membrane liner sheet when curled into a cylinder, showing first stage of the formation of the liner during which the vertical seam of the liner is formed.

FIG. 5 b is in perspective view, the liner of FIG. 5 a with the vertical seam formed to close the cylinder and the lower end of the cylinder closed along a bottom linear seam.

FIG. 5 c is, in perspective view, the liner of FIG. 5 b with the lower corners folded to the center to abut together along the center portion of the bottom linear seam.

FIG. 6 is, in elevated view, the fluid tight membrane liner sheet of FIG. 5 c with the lower corners folded into place on the bottom linear seam.

FIG. 7 is, in plan detailed view, the lower portion of the fluid tight membrane liner sheet of FIG. 6 with a double angle iron clamp applied to secure corners of the liner bottom seam.

FIG. 7 a is, an edge view along line 7 a-7 a in FIG. 7

FIG. 8 is, in perspective view, the double angle iron clamp of FIG. 7.

FIG. 9 is, in plan view, an alternative embodiment of the heat reservoir housing shell of the heat reservoir of the present invention wherein the housing is formed as an open top and open bottom rectangular box made of two formed sheets of metal fastened together.

FIG. 10 is, in front perspective view, one half of the rectangular reservoir housing of FIG. 9 in its assembled form showing the rib locations, insulation locations, flanges, and flange bolt holes.

FIG. 11 is, in plan view, the ribs of the rectangular reservoir housing of FIG. 10.

FIG. 12 is, in plan view, the heat reservoir housing shell of FIG. 10 completed and prior to installing the fluid tight liner.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Heat reservoir 1 provides a holding tank for liquid to be stored in liquid holding cavity 8. The holding tank is for use in non-pressurized liquid storage applications, most typically as a heat reservoir for solar heating applications.

The supporting structure of reservoir 1 is constructed of sheet metal. In the embodiments of FIGS. 1-8, the sheet metal is rolled into a cylinder 5. Flanges 9 are formed along the mating edges of the rolled sheet. Lengths of angle iron 15 are positioned along the outer surfaces of abutting flanges 9. Bolts 16 are journalled through apertures in both angle iron 15 and flanges 9 to create a structurally sound seam along flanges 9, thereby securing the sheet as an open ended cylinder 5.

The cylinder 5 is placed onto an insulating base 2 such as Styrofoam™ or other insulating structural material, and then wrapped in an insulating blanket 3 of fiberglass or Styrofoam or other insulators. The insulation may be covered on its outside with metallic foil such as aluminum foil or other covers.

Screws 17 or other fastening means are inserted through apertures formed around the upper rim of the open cylinder 5. Screws 17 are screwed through the sheet metal of cylinder 5 from the inside of the cylinder outward, thus leaving sharp ended protrusions that may serve as liner anchors.

The liner is formed by folding and clamping sheets of fluid tight membrane. The membrane is flexible, and is advantageously also resilient. For example, two sheets may be bonded together using adhesive along seam 11 to form a long rectangular sheet which may be then rolled into a cylinder of approximately the same diameter as cylinder 5. The free ends of the rolled rectangular sheet are overlapped and bonded along a further vertical seam 11 to form a cylinder. The edge 23 of the fluid tight membrane sheet 6 cylinder selected to be the bottom of the tank or reservoir liner is similarly bonded into a seam 18 by coating the inside surface of the lower edge of the cylinder with an adhesive or other bonding agent and clamping those inside surfaces together. This forms a cylindrical bag liner that is open at its upper end. The corners 18 a of the resulting straight edged seam 18 are then folded in direction B to bring the corners in towards the axis A (shown to be parallel to seam 11) Folding in corners 18 a to abut together over the center portion 18 b forms a substantially wedge-shaped lower portion of the liner bag. Once folded in direction B the corners 18 a are pulled down in direction C such that the bottom edge of the folded corners 18 a and the bottom edge of the center portion 18 b of linear seam 18 are substantially collinear.

Pulling corners 18 a down in direction C so as to overlay the corners on the center portion 18 b of the bottom linear seam 18 causes the upper rim 6 a of the bag liner to open in direction D, thereby assisting in forming the open shape of the liner. Initially the shape of the liner is frustoconical in the upper portion and wedge-shaped towards the bottom so as to narrow down to linear seam 18. The pre-forming of the liner helps ease installation of the liner in the housing shell, and provides an inexpensive sealed liner for use in non-pressure, i.e. un-regulated vessels.

The seam 24 comprising the overlapped corners 18 a overlapped along the center portion 18 b of seam 18 is then clamped using a clamping means 20 such as angle iron 21 and fasteners 22. The corners 18 a of bottom seam 18 are clamped over and onto center portion 18 b so as to maintain the integrity of the seam corners 18 a and thereby prevent leakage once the bag liner is installed in the housing shell and filled with liquid. Once the seams have been established and secured the bag liner is lowered into the open end of the cylindrical housing shell, and the upper edge of the bag liner is folded to form lip 12 over the upper rim of the cylinder. Lip 12 is impaled onto the outwardly pointing fasteners 17, thereby securing the bag liner to the sheet metal cylinder 5, forming fluid tight tank or reservoir 1. As the liner is lowered into the cavity 8 the lower wedge-shaped portion of the liner folds under the upper portion as the lower portion contacts the base 2. This forms the floor of the liner. As fluid fills the liner, the upper portion of the liner confirms to the interior of the cavity.

Ports are cut in the walls of the cylindrical reservoir 1 at various locations and elevations as necessary to plumb in inlet and outlet tubes both for the reservoir fluid and for any heat exchanger and instrumentation placed into the reservoir. Fluid tight seals are formed around the tubes and instrumentation cabling to maintain the fluid tight integrity of the reservoir. Cavity 8 in reservoir 1 is filled with heat exchange fluid such as water.

A second fluid tight membrane sheet 7 is cut in a circle of diameter larger than the diameter of the upper rim of cylinder 5. Sheet 7 is cut with sufficient excess material so that the circumferential edge may be folded downward also impaled onto the outwardly pointing ends of fasteners 17, thus sheet 7 may be affixed over the reservoir opening by being attached to the outwardly protruding fasteners 17. A structurally supporting member such as sheet metal, wood, chloroplast board or other is cut to the fit the top of the reservoir, and is fitted along with a covering of insulation 4 and weatherproof material such as metalized paper like aluminum foil or similar. All insulation seams and interfaces are sealed with seam tape or other sealants to reduce the likelihood of heat loss.

Instrumentation such as temperature and flow sensors may also be installed in the reservoir for monitoring and control.

FIGS. 9-12 illustrate an alternative embodiment of the present invention which may be constructed by forming two metal sheets 27 into half profiles of an open top and bottom rectangular box as. Each sheet 27 is folded to form the corners of the bisected open top and bottom rectangular box. Flanges 9′ are formed at the interfacing edges of the sheets where the sheets match up to form the open top and bottom rectangular box. The two sheets 27 are assembled on an insulating base 2′ with each of the two flanges 9′ mating with those of the opposite sheet 27. Angle iron backing 15′ bolsters each flange 9′. Each Flange 9′ is sandwiched between two pieces of angle iron 15′. Bolts fasten the made iron onto the flanges.

Ribs 28 and 29 are profiled in an arc like fashion. Ribs 28 and 2 a are mounted in vertically spaced apart array elevations along the height of the walls of the rectangular reservoir 26. The flat sides of the ribs mate with the inside surface of the metal sheet 27. Ribs 28 and 29 may be frictionally secured in place by a tolerance fit between opposing walls of the open top and bottom rectangular box. The ribs 28 and 29 are installed in sets of four, that is, on the same elevation one rib will be mounted on each end and on each side such that two adjacent rib ends have an interference fit with corner brace 33 mounted in the corners of the rectangular reservoir 26. The number of ribs sets required depends on the height of the rectangular reservoir 26. Ribs are shown at three elevations by way of example. Insulation 30, which may be spray-on polyurethane, or other foam insulation material, is placed between the ribs. Insulation is also placed between the upper and lower most ribs and the edge of the open-ended rectangular box. Additional insulation 31 placed in the corners. After installing a number of rib sets 28 and 29 at various elevations, sheets of material 32 are formed and fastened by stapling or other means to the curved surfaces of the ribs 28 and 29 secured to each inside face of the rectangular open top and bottom box, and fitted with an interference fit with the sheet 32 of the adjacent face where they meet in the corners.

A fluid tight liner 6, as described above is placed into the open ended rectangular box 26 and fastened to the rim by liner anchors 10 similar to that used for cylindrical reservoir 1. Ports are cut into the walls at various locations and elevations to plumb in the inlet and outlet tubes both for the reservoir fluid and for any heat exchanger and instrumentation placed into the reservoir, and then fluid tight seals are formed around the tubes and instrumentation cabling to maintain the fluid tight integrity of the reservoir.

The cavity in reservoir 26 is filled with heat exchange fluid such as water. A second fluid tight membrane sheet 7 generally cut in a rectangular manner, larger than the opening or the rectangular box 26 with enough excess to be similarly impaled onto the outwardly pointing fasteners 17, and is placed over the reservoir opening and attached to the outwardly protruding fasteners 17. A structurally supporting member such as sheet metal, wood, chloroplast board or other is cut to the fit the top of the reservoir, and is fitted along with a covering of insulation 4 and weatherproof material such as metalized paper like aluminum foil or similar. All insulation seams and interfaces are sealed with seam tape or other sealants to reduce the likelihood of heat loss.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. 

1. a non-pressurized fluid reservoir comprising: a housing shell defining a cavity, a flexible water impervious bag-shaped liner mounted in said cavity so as to substantially fill said cavity when said liner is filled with fluid, wherein said liner is formed from a flexible water-imperious sheet by forming said sheet into a cylinder, then forming a water-tight first seam along a bottom edge of said cylinder, folding outer corners of said first seam over, so as to overlap with a center portion of said first seam, and so that bottom edges of said outer corners, once so folded over, register substantially co-linearly within a bottom edge of said center portion of said first seam, whereby an upper portion of said liner is urged to bag open thereby forming said upper portion in a substantially frustoconical shape, said upper portion contiguous with a lower portion of said liner, said lower portion substantially wedge shaped, and wherein said bottom corners overlapping said center portion of said first seam are sealed onto said first seam so as to form a second seal.
 2. The reservoir of claim 1 wherein said sheet is formed into said cylinder by sealing opposite ends of said sheet to one another along a third seam once said sheet has been curled into a cylindrical shape.
 3. The reservoir of claim 2 wherein said housing shell is substantially cylindrical and sized so that said upper portion of said liner fits snugly inside said cavity.
 4. The reservoir of claim 3 wherein said liner is resilient.
 5. The reservoir of claim 4 wherein said lower portion of said liner folds under said upper portion of said liner when said liner is mounted in said cavity, said liner so mounted to register an upper edge of said liner with an upper rim of said housing shell, wherein said rim extends around an upper opening into said cavity, said lower portion said folding under said upper portion to form a floor surface of said liner and to flatten said floor surface of said liner down against a substantially horizontal supporting surface under said housing shell.
 6. The reservoir of claim 5 wherein said housing shell is open-bottomed, and said supporting surface is a separate platform surface, separate from said shell.
 7. The reservoir of claim 5 wherein, when fluid fills said liner in said cavity, said floor surface of said liner spreads out substantially to meet wall of said shell.
 8. The reservoir of claim 8 wherein said upper edge of said liner is foldable to form a lip, and wherein said rim of said housing shell further comprises a racially spaced apart array of liner-engaging protrusions to engage and lock to said lip.
 9. The reservoir of claim 1 further comprising an insulating blanket mounted around said housing shell, an insulated lid for closing an upper opening into said cavity, and an insulated base on which is mounted said housing shell.
 10. The reservoir of claim 1 further comprising a clamp, and wherein said clamp is clamped over said bottom corners and said center portion of said first seam when said bottom corners are abutted together and overlaid over said center portion of said first seam. 